不同品级铝矾土均化烧结性能及微观结构的研究

Study on Homogenized Sintering Performance and Microstructure of Different Grades of Bauxite

利用TG-DSC-DTG对不同品级铝矾土进行热分析,研究不同品级铝矾土在不同温度下的均化烧结情况,利用XRD、SEM对均化矾土熟料的物相组成和微观结构进行研究。结果表明:Al2O3含量为89%(S级)、84%(I级)和74%(IIA级)的铝矾土,其最佳均化烧结温度分别为1580℃、1600℃和1650℃,各级均化矾土熟料在最佳烧结状态下的晶体结构和生长形态为:S级、I级均化矾土熟料主要为发育良好的刚玉晶粒,大部分呈长柱状,少量呈等轴状,晶粒间结合紧密,杂质均匀分布在晶界的玻璃相中;IIA级均化矾土熟料中刚玉相与莫来石相共存,晶粒发育良好,莫来石晶体为长柱状。

Different grades of bauxite were analyzed by TG-DSC-DTG. The homogenized sintering condition of different grades of bauxite at different temperatures was studied,and the phase composition and microstructure of homogenized bauxite were determined and observed by XRD and SEM. The results indicate that the optimum sintering temperature of 89%( S grade),84%( I grade) and 74%( IIA grade)Al2O3bauxite is 1580 ℃,1600 ℃ and 1650 ℃,respectively. The crystal structure and growth morphology of different grades of homogenized bauxite in the optimal sintering condition show that the main phase of S grade and I grade homogenized bauxite is well developed corundum crystal; most are long columnar,and some are equiaxed; the grains combine closely; the impurities distribut evenly in the glass phase of the grain boundary; corundum and mullite phase coexist in IIA grade homogenized bauxite; the crystals develope well; the mullite crystals are columnar.